Thanks to the development of IT technology, high performance, acceleration, high integration, and miniaturization (thinning) of recent electronic apparatuses (e.g., smartphones, smart televisions (TVs), computers, tablet PCs, displays, digital cameras, camcorders, MP3 players, game consoles, navigation, etc.) are progressing. Recent trends in electronic apparatuses require a technique of transmitting large amounts of data, such as high-resolution or 3-dimensional (3D) image contents, between boards in apparatuses. Thus, signal attenuation, noise, electromagnetic interference (EMI)/electromagnetic compatibility (EMC), impedance matching, crosstalk, skew, connection wiring miniaturization, etc. have been highlighted as big issues.
In general, copper (Cu)-based wirings, i.e., electrical connectors, have been used to transmit data in apparatuses. However, the copper-based wirings neither meet the needs of high-speed transmission of large amounts of data nor solve various technical issues in accordance with the above-described latest trends in electronic apparatuses. As a technique for solving the technical issues, an optical wiring technique has recently been studied and developed. In other words, optical wirings enable high-speed transmission of big amounts of data by replacing parallel electrical signal lines of dozens of channels with serial optical signal lines, and may solve technical problems, such as noise, EMI/EMC, impedance matching, crosstalk, skew, and connection wiring miniaturization.
FIG. 1 is a perspective view of an embodiment of a conventional optical cable module used to connect boards in an apparatus. The optical cable module illustrated in FIG. 1 is disclosed in Japanese Patent Registration No. 4631671 (entitled “Optical cable module and electronic apparatus having the optical cable module”) [hereinafter referred to as ‘Conventional art 1’] that will be described below.
The optical cable module of FIG. 1 includes a transmitter 10a and a receiver 10b. The transmitter includes a VCSEL chip 3a, an electrode pad 5a, a bonding wire 7a, a liquid resin 8a, and a height support member 4a disposed on a substrate 6a. The receiver includes a photodiode (PD) chip 3b, an electrode pad 5b, a bonding wire 7b, a liquid resin 8b, and a height support member 4b disposed on a substrate 6b. A connection wiring between the transmitter and the receiver includes an optical waveguide 2.
On analysis of operations of the optical cable module of FIG. 1, an electric signal (i.e., image data) of a mainboard connected to the transmitter is converted into an optical signal by the VCSEL chip 3a under the control of a driver integrated circuit (driver IC) (not shown) via the electrode pad 5a disposed on the substrate 6a. The optical signal is vertically emitted from the VCSEL chip 3a in an upward direction, reflected by a 45° mirror surface of an end tip of the optical waveguide 2, and transmitted to the receiver via the optical waveguide 2.
In the receiver, the optical signal is vertically reflected in a downward direction via the 45° mirror surface of the end tip of the optical waveguide 2 and incident on the PD chip 3b disposed on the substrate 6b. The optical signal is converted into an electric signal by the PD chip 3b under the control of a transimpedance amplifier (TIA) (not shown) via the electrode pad 5b disposed on the substrate 6b, and input to a display board connected to the receiver.
FIG. 2 is a perspective view of an embodiment of a conventional photoelectric conversion module used to connect chips in an apparatus. The photoelectric conversion module illustrated in FIG. 2 is disclosed in Korean Patent Registration No. 810665 (entitled “photoelectric conversion module and method for manufacturing the same”) [hereinafter referred to as ‘Conventional art 2’] that will be described below.
The photoelectric conversion module illustrated in FIG. 2 includes a transmitter 200 and a receiver 300 disposed on a printed circuit board (PCB) 500 and includes an optical waveguide 400 as a connection wiring between the transmitter and the receiver. The transmitter 200 includes an IC substrate 200a, electrode pads 211 and 212 formed on a top surface of the IC substrate 200a, an electrode pad 220 formed on a side surface of the IC substrate 200a, a driver IC 230 bonded to the top surface of the IC substrate 200a via the electrode pads 211 and 212, and a VCSEL chip 251 bonded to the side surface of the IC substrate 200a via the electrode pad 220.
The receiver 300 includes an IC substrate 300a, electrode pads 311 and 312 formed on a top surface of the IC substrate 300a, an electrode pad 320 formed on a side surface of the IC substrate 300a, a TIA 330 bonded to the top surface of the IC substrate 300a via the electrode pads 311 and 312, and a PD chip 350 bonded to the side surface of the IC substrate 300a via the electrode pad 320.
FIG. 3 is a perspective view of an embodiment of a conventional optoelectronic hybrid connector used to connect boards in an apparatus. The optoelectronic hybrid connector illustrated in FIG. 3 is disclosed in Japanese Patent Publication No. 2010-266729 (entitled “optoelectronic hybrid connector”) [hereinafter referred to as ‘Conventional art 3’] that will be described below.
The optoelectronic hybrid connector of FIG. 3 includes a plug 20 mated with an electrical connector 30 (which is called a receptacle) mounted on a board in an apparatus. The plug 20 includes a housing 21, an electrical terminal 22 and a ground terminal 23 mounted on both side surfaces of the housing 21, a ground plate 24 mounted on an inner bottom surface of the housing 21, a VCSEL chip 26 disposed on a sub-mount 25 mounted on the ground plate 24, a driver IC 27, a bonding wire 28 configured to function as a wiring for connection of the electrical terminal 22 and the ground terminal 23 with the VCSEL chip 26 and the driver IC 27, and an optical fiber 29 inserted into the housing 21.